In forming the organic light emitting diode display panel, the evaporation-deposition process is required. In the evaporation-deposition process, the use of the mask is necessary to form a specific pattern. In order to increase production efficiency, it is common to deposit on a large motherboard and then to divide the motherboard into a plurality of small array substrates. Correspondingly, the mask comprises a mask frame and a plurality of mask strips fixed on the mask frame. A plurality of through-holes can be formed in the mask strip. Evaporation-deposition material can be deposited on the motherboard through these through holes to obtain a corresponding pattern.
In order to ensure uniform stress on the mask strip and reduce wrinkles, through holes are also formed on the edge of the mask strip. However, in the process of the deposition of the material, a portion of the motherboard corresponding to the edge of the mask strip is not required to deposit the material. Therefore, a shielding bar is necessarily used to shield the edge of the mask strip.